On the turn I caught a flushdraw and for the second barrell I thought he might had a hand he liked, so I called again; I couldn't really check/raise semi-bluff on the 6 — figuring he had anything like AJ, AT, KT, KJ or QJ he would have a hard time letting go of his hand.

The river card isn't so scary, but he checked and I insta-shoved figuring I was beat. Was that a TERRIBLE bluff or what? I checked later and he had WTS 37 so... I guess I would have avoided that if I had seen earlier his stats...

Preflop: looks loose. That "20" was over what sample? Sample is key here and even then 98 might be too light because if villain 3-bets that wide of a range he 3-bets all broadway type hands and I would find it hard to believe that this is over any meaningful sample.

As played we can also raise/fold the flop with our weaker draw that has 9 high.

As played look at the range you gave him on the turn. Part of that bets the river but how much of that can he ck/call?

And we bet WITH a pair so what exactly are we looking for him to fold? 99, Tx, Jx?